Air-handling unit

ABSTRACT

The present invention provides an air-handling unit that can supply air, to a desired space, which is cold, which is cooler than the set point of the thermostat for that space and hence is referred to as cool air, which is warmer than that set point and hence is referred to as warm air, or which is hot. That unit can operate even when very low pressure air is supplied to it; and hence it is connectable to a conventional low pressure cold air duct. That unit may have a heat source incorporated into it, may utilize air from that space which is cooler than that set point and hence can be referred as cool air, and may utilize air from that space which is warmer than that set point and hence can be referred to as warm air. Dampers in that unit control the amount of cold air and cool air that is supplied to that space, and a blower and the heat source in that unit control the amount of warm air and hot air which is supplied to that space. Backdraft dampers in that unit permit aspiration of cool or warm air, but can substantially prevent the escape of any air from that unit even if a super-atmospheric downstream pressure develops.

This is a division of application Ser. No. 204,901, filed Nov. 7, 1980,now U.S. Pat. No. 4,328,926, which is a continuation of application Ser.No. 907,682, filed May 19, 1978, now abandoned.

SUMMARY OF THE INVENTION

The present invention provides an air-handling unit that can supply air,to a desired space, which is cold, which is cooler than the set point ofthe thermostat for that space and hence is referred to hereinafter ascool air, which is warmer than that set point and hence is referred tohereinafter as warm air, or which is hot. That unit can operate evenwhen very low pressure air is supplied to it; and hence it isconnectable to a conventional low pressure cold air duct. That unit mayhave a heat source incorporated into it, may utilize air from that spacewhich is cooler than that set point and hence is referred to hereinafteras cool air, and may utilize air from that space which is warmer thanthat set point and hence is referred to hereinafter as warm air. Whenonly cold air is required, cold-air dampers within that unit will beopen; but when cool air is required, those cold-air dampers will beintermediate their open and their minimum-flow positions. When hot airis required, the heat source will be supplying heat and the cold-airdampers will be in their minimum-flow positions; but when only warm airis required, that heat source will be supplying little or no heat. Itis, therefore, an object of the present invention to provide anair-handling unit which can supply air to a desired space, which canoperate even when very low pressure air is supplied to it, which isconnectable to a conventional low pressure cold air duct, which may havea heat source incorporated into it, which may utilize cool air from thatspace, and which may utilize warm air from that space.

Some of the air-handling units provided by the present invention havebackdraft dampers. Those dampers permit those units to aspirate air intothem, but will substantially prevent the escape of any air from thoseunits, even if a super-atmospheric downstream pressure develops. As aresult those units can be incorporated into a duct system at any desiredlocation between the primary air-moving unit and downstream ductoutlets. It is, therefore, an object of the present invention to providean air-handling unit which can be incorporated into a duct system at anydesired location between the primary air-moving unit and the downstreamduct outlets, and which can permit air to be aspirated into it when thedownstream pressure is below the ambient pressure, but which willsubstantially prevent the escape of any air when that downstreampressure exceeds that ambient pressure.

Other and further objects and advantages of the present invention shouldbecome apparent from an examination of the drawing and accompanyingdescription.

In the drawing and accompanying description, several preferredembodiments of the present invention are shown and described, but it isto be understood that the drawing and accompanying description are forthe purpose of illustration only and do not limit the invention and thatthe invention will be defined by the appended claim.

BRIEF DESCRIPTION OF DRAWING

In the drawing, FIG. 1 is a partially-broken, vertical section throughpart of a building in which one preferred embodiment of air-handlingunit provided by the present invention is mounted,

FIG. 2 is a vertical section through part of a building in which asecond preferred embodiment of air-handling unit provided by the presentinvention is mounted,

FIG. 3 is a vertical section through part of a building where a thirdpreferred embodiment of air-handling unit provided by the presentinvention is mounted,

FIG. 4 is a vertical section through part of a building where a fourthpreferred embodiment of air-handling unit provided by the presentinvention is mounted, and

FIG. 5 is a vertical section of a fifth preferred embodiment ofair-handling unit provided by the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring particularly to FIG. 1, the numeral 20 generally denotes awall of a building; and a sill 22 and a header 24 are located,respectively, at the bottom and top of that wall. A stud 26, plussimilar studs not shown, extends between that sill and that header. Thenumeral 28 denotes wallboard, plaster-on-lath, or the like which definesthe left-hand face of wall 20. The numeral 30 denotes wallboard,plaster-on-lath, or the like which defines the right-hand face of thatwall. A generally-rectangular opening 32 is formed in that left-handface; and generally-rectangular openings 34 and 36 are formed in thatright-hand face. The opening 36 is close to the bottom of wall 20, theopening 32 is close to the top of that wall, and the opening 34 is inregister with, but is considerably larger than, the opening 32.

The numeral 39 denotes the ceiling, and the numeral 40 denotes thefloor, of a room 37 which has one side thereof defined by the wall 20.That room could be a room, corridor, entry area, hall, auditorium, workarea or other space in a home, club, store, office building, publicbuilding, factory, warehouse, industrial building, or other structure. Ahorizontal member 38 is spaced above the ceiling 39 to help define aplenum, such as an attic, or a between-floor space, which can receivewarm air from the room 37--either directly through grilles, not shown,in the ceiling 39, through openings in or adjacent to lighting fixtures43 in that ceiling, or indirectly by leakage through that ceiling. Adischarge outlet 41 is provided in the ceiling 39; and, if the room 37is large, further discharge outlets will be provided in that ceiling. Abaseboard 42 abuts the right-hand face of the wall 20 adjacent the floor40. A grille 44 is disposed within the opening 36; and, depending uponthe height of the room 37, that grille could be displaced just a fewfeet, or could be displaced many feet, below the ceiling 39.

The numeral 46 denotes a conventional low pressure, cold-air duct whichreceives cold air from a primary air-moving unit and refrigeration unitnot shown. The duct 46 will be suitably supported by hangers of standardand usual design, not shown. Tape 48 of standard and usual design willbe used to seal the joint between the opening 32 in the left-hand faceof wall 20 and duct 46.

The numeral 50 denotes a hinge that is secured to the upper wall of duct46 and to the left-hand end of an enlongated vane or damper 52. Thathinge could be an elongated piano-type hinge or could be a number ofaligned short hinges. The vane 52 is planar throughout the greaterportion of its area but is bent upwardly adjacent the right-hand endthereof, and it has the free edge thereof bent as a re-entrant fold. Thenumeral 54 denotes a hinge which is secured to the lower wall of duct 46and to the left-hand end of a vane or damper 56 which is a mirror imageof vane 52. The numeral 58 denotes an axle which is rotatably mounted,which has a lever 60 fixedly secured to one end thereof, and which has acrank arm 66 fixedly secured to the other end thereof. A connecting link62 is pivotally secured to one end of lever 60 and to the vane 52, and aconnecting link 64 is pivotally secured to the other end of that leverand to the vane 56. An actuating motor 70, which is shown as a pneumaticmotor but which could be an electric, electronic, hydraulic, or othermotor, has the actuator 72 thereof connected to the crank arm 66 by aconnecting rod 68. That motor can cause the right-hand ends of the vanes52 and 56 to move to a minimum-flow position, or can cause those vanesto move to their full open position, wherein the right-hand ends thereofengage resilient stops 102 and 104. Further, the motor 70 can set thosevanes in any desired positions intermediate their minimum-flow and fullopen positions; and FIG. 1 shows one such intermediate position. Intheir minimum-flow position, the free ends of the vanes 52 and 56 couldabut each other to effectively block the passage of cold airtherebetween, or those free ends could be held a short distance apart topermit a limited amount of cold air to pass between them. In theirfull-open positions, the vanes 52 and 56 will reduce the pressure dropacross the air-handling unit of FIG. 1 to a minimum pressure drop of onehundredth of an inch water gauge. As a result, that unit can be usedwith very low pressure cold air ducts.

The numeral 74 denotes an angle iron which constitutes the upper part ofa frame that is mounted adjacent the opening 34 in the right-hand faceof wall 20; and the numeral 76 denotes an angle iron which defines thebottom part of that frame. Angle irons which define the sides of thatframe are not shown, but they extend between and are rigidly secured tothe angle irons 74 and 76.

The numeral 80 generally denotes a housing for the vanes 52 and 56; andthat housing has an upper wall 82 which has a horizontally-directedleft-hand portion, an intermediate portion which inclines downwardlyfrom upper left to lower right, and a horizontally-extending right-handportion. The numeral 84 denotes the bottom wall of the housing 80; andit has a horizontally-extending left-hand portion, an intermediateportion which inclines upwardly from lower left to upper right, and aright-hand vertically-directed, upwardly-extending portion. The numeral86 denotes one side wall of the housing 80; and that side wall isgenerally pentagonal in configuration.

The other side wall, not shown, also will be generally pentagonal inconfiguration. The top wall 82 will be releasably secured to angle iron74 and to an angle iron 101; and it will abut the upper edges of sidewall 86 and of the other side wall. The bottom wall 84 will bereleasably secured to angle iron 76 and to an angle iron 103; and itwill abut the lower edges of side wall 86 and of the other side wall.Tape 78 is used to seal the joint between the right-hand face of wall 20and housing 80.

The numeral 88 denotes an angle iron which is secured to the top wall ofduct 46 adjacent the opening 34 in the right-hand face of wall 20. Thenumeral 90 denotes an angle iron which is secured to the bottom wall ofthat duct adjacent that opening. The numeral 92 denotes a screen, madeof hardware cloth or other porous material, which is secured to angleirons 74 and 88 and which fills the space between the upper edge ofopening 34 and the top wall of duct 46. The numeral 94 denotes a furtherscreen of hardware cloth or other porous material which is secured toangle irons 90 and 76 and which fills the space between the lower edgeof opening 34 and the bottom wall of duct 46. The screens 92 and 94incline downwardly from upper left to lower right at angles of aboutfour degrees from the vertical. The numeral 96 denotes a backdraftdamper which is secured to angle iron 74 or to the upper edge of screen92; and that backdraft damper will normally be planar in configurationand will normally abut the right-hand face of screen 92. However, thatbackdraft damper is very flexible; and it will respond to even a verysmall reduced pressure at the right-hand face thereof to flex to theposition shown by FIG. 1. The numeral 98 denotes a backdraft damperwhich is secured to angle iron 90 or to the upper edge of screen 94; andthat backdraft damper normally will be planar in configuration and willnormally abut the right-hand face of that screen. However, thatbackdraft damper will respond to even a very small reduced pressure atthe right-hand face thereof to flex to the position shown by FIG. 1.

The numeral 100 denotes a short duct which telescopes within theright-hand end of housing 80; and resilient stop 104 is secured to thatduct. Resilient stop 102 is secured to the bottom of angle iron 101. Anopening 106 is provided in the top of duct 100 adjacent the left-handend of that duct. A further duct 108 is connected to the outlet of duct100 by an angle iron joint 120 of standard and usual design. An arm 121of duct 100 extends downwardly to, and supports, discharge outlet 41.

The numeral 122 denotes an L-shaped housing which is connected to, andwhich extends upwardly from, the opening 106 in duct 100. A curved vane124 is secured to housing 122; and that vane curves downwardly and tothe right into the duct 100. The numeral 126 denotes a heat source thathas an enclosure 128; and that enclosure is connected to the left-handend of L-shaped housing 122. That heat source is shown as a hot watercoil; but it could be a steam coil, an electric resistance element, or agas-fired heater. Backdraft dampers 129 are mounted at the outlet of theheat source 126; and those dampers can be standard and usual air-movedmetal dampers. The numeral 130 denotes a motor-driven, multi-vane blowerwhich has the outlet thereof secured to the enclosure 128 for heatsource 126. An inlet pipe 132 has a valve 134 therein; and that valvecan be selectively set and held in open, closed, or any intermediateposition by a valve controller 136. The numeral 138 denotes a thermostatwhich is located within the room 37, and which provides a variableoutput, rather than an on-off output, in response to changes in thetemperature of the ambient air. One such thermostat is a pneumaticthermostat; but electric, electronic, thermistor-type, and othervariable output thermostats could be used. The numeral 140 denotes acontrol unit which will respond to the output of thermostat 138 toprovide variable outputs, rather than on-off outputs, that can controlmotor 70, control the motor for blower 130, and control the valvecontroller 136. The thermostat 138 will have a control range of two tothree degrees Fehrenheit; and it will have a set point intermediate theupper and lower limits of that range. That set joint usually will be,and throughout this description will be considered to be, at themidpoint of that range.

If the temperature of the air adjacent thermostat 138 is above the upperlimit of the control range of that thermostat, that thermostat willprovide an output which will cause control unit 140 to develop outputsthat will keep the motor of blower 130 inactive, will cause valvecontroller 136 to leave valve 134 closed, and will cause motor 70 tohold vanes 52 and 56 in their full-open position. At such time, a fullvolume of low pressure cold air from duct 46 will pass through duct 100,below and past the vane 124, and enter duct 108--where some of that coldair will pass through arm 121 and outlet 41 and enter room 37, while therest of that cold air will continue to move through that duct. The vane124 will minimize any tendency of the cold air to enter the L-shapedhousing 122 and to escape through the heat source 126 and blower 130. Inaddition, the backdraft dampers 129 will help prevent any escape of coldair through that heat source and those dampers.

The cold air which enters the room 37 will tend to decrease thetemperature of the air adjacent thermostat 138. However, as long as thetemperature of the air adjacent that thermostat is above the upper limitof the control range of that thermostat, that thermostat will continueto provide an output which will cause control unit 140 to developoutputs that will keep the motor of blower 130 inactive, will causevalve controller 136 to leave valve 134 closed, and will cause motor 70to hold vanes 52 and 56 in their full-open position. Consequently,maximum cooling effect will be supplied to the room 37; and hence thetemperature of the air adjacent thermostat 138 will decrease.

When the temperature of that air decreases to the point where it isbelow the upper limit of the control range, but is above the set pointof that thermostat, that thermostat will develop an output which willcause control unit 140 to develop outputs that will continue to keep themotor of blower 130 inactive and will continue to cause valve controller136 to leave valve 130 closed, but will cause motor 70 to move the vanes52 and 56 inwardly from their full-open position to a positionintermediate that position and their minimum-flow position. As thosevanes move to that intermediate position, they will reduce the amount ofcold air that will pass through duct 46, and thence through ducts 100and 108 into room 37. Those vanes also will permit the air which passesthrough them from duct 46 to develop and maintain a reduced pressureadjacent the right-hand faces of the backdraft dampers 96 and 98. As aresult, those backdraft dampers will move to the positions of FIG. 1;and hence will permit air to be drawn upwardly through grille 44 inopening 36, upwardly through the wall 20, through the screens 92 and 94,through the housing 80, between the stops 102 and 104 and the right-handends of vanes 52 and 56, and then mixed with the cold air from duct 46.

The grille 44 is located adjacent the floor 40 of room 37; and hence thetemperature of the air which is drawn into that grille, and ultimatelymixed with the cold air from duct 46, will be relatively cool.Importantly, the temperature of the air which is drawn into the grille44 will be lower than that of the air adjacent thermostat 138; and hencethe air which is aspirated through the spaces adjacent the free ends ofvanes 52 and 56 will provide a cooling effect. As a result, thataspirated air will reduce the load on the primary refrigeration unit ofthe overall system. Also, by reducing the amount of air that is movedthrough the duct 46, the vanes 52 and 56 will reduce the load on theprimary air-moving unit. All of this means that by facilitating theaspiration of air--which is cooler than the set point temperature of thethermostat--into the cold air from duct 46, the vanes 52 and 56 saveenergy by reducing the horsepower hour consumption of that primaryrefrigeration unit and of that primary air-moving unit.

The cooling effect provided by the admixed aspirated cool air and thecold air from duct 46 will cause the temperature of the air adjacentthermostat 138 to continue to decrease. As that temperature decreases,but while that temperature is above the set point of that thermostat,the output of that thermostat will cause the control unit to continue tokeep the motor of blower 130 inactive and will continue to cause valvecontroller 136 to leave valve 130 closed. However, that output willchange sufficiently to cause the motor 70 to progressively move thevanes 52 and 56 inwardly as the temperature of the air adjacentthermostat 138 moves downwardly toward the set point of the thermostat.The closer that temperature approaches that set point, the closer thefree ends of vanes 52 and 56 will be moved toward each other; and,conversely, the further that temperature is displaced from that setpoint, the further those free ends will be moved away from each other.The combination of the cold air from the duct 46 and the cool air fromthe lower area of room 37 can, depending upon the amount of heatgenerated within, or supplied to, that room, hold the temperature of theair adjacent thermostat 138 close to the set point of that thermostat.

In the foregoing description, it was assumed that the temperature of theair adjacent thermostat 138 tended to rise above the set point of thatthermostat. If, on the other hand, that temperature tended to fall belowthat set point, the output of that thermostat would cause the controlunit 140 to provide outputs which would cause motor 70 to hold the vanes52 and 56 in their minimum-flow position, would cause the valvecontroller 136 to keep valve 134 closed, and would cause the motor ofblower 130 to start operating at a low speed. The air which was drawninto the intake of the blower 130 would be from the plenum defined byhorizontal member 38 and ceiling 39. That air usually will be warmerthan the air adjacent thermostat 138; because it will be drawn from theupper, and hence warmer, area of room 37, and also because it will beheated as it rises upwardly through openings in or adjacent to thelighting fixture 43 and through openings in or adjacent to otherlighting fixtures for room 37 and adjacent rooms. If the horizontalmember 38 was the roof of the building, and if that roof was notinsulated, the air in the plenum between that member and the ceiling 39would be cool in cold weather. However, a duct, not shown, could beprovided to conduct air from a warm place in the building to the intakeof blower 130. Whether the air in the plenum between member 38 and theceiling 39 was warm or warm air was supplied to the intake of blower 130by a duct, the warmth of the air from that blower would tend to keep thetemperature of the air adjacent thermostat 138 from falling below theset point of that thermostat.

However, if that temperature were to fall below that set point, thethermostat 138 would provide an output which would enable control unit140 to cause the blower 130 to operate at a higher speed. Thereupon,that blower would increase the flow of warm air into the room 37, andwould thereby tend to keep the temperature of the air adjacentthermostat 138 close to the set point of that thermostat. If, despitethe increased flow of warm air into the room 37, the temperature of theair adjacent that thermostat were to closely approach the lower limit ofthe control range of that thermostat, the control unit 140 would causethe blower 130 to operate at full speed. The resulting maximum flow ofwarm air into room 37 would tend to prevent any further decrease in thetemperature of the air adjacent thermostat 138. However, if thetemperature of the air adjacent that thermostat were to reach the lowerlimit of the control range, the control unit 140 would cause valvecontroller 136 to open valve 134. The resulting heat in the heat source126 would be transferred to the air passing through that heat source;and that heat would be added to the heat which the warm air already hadas it entered the inlet of blower 130. The combined heat of that warmair and the heat from heat source 126 would coact to keep thetemperature of the air adjacent thermostat 138 from decreasing anyfurther and, instead, would cause that temperature to rise toward theset point of that thermostat. As long as the temperature of the airadjacent thermostat 138 was below the lower limit of the control rangeof that thermostat, the control unit 140 would keep the blower 130operating and would keep the valve 134 open. As that temperature roseabove that lower limit, the control unit 140 would permit the valve 134to close; but the blower 130 would continue to supply warm air to room37. If the temperature of the air adjacent thermostat 138 continued torise, the speed of that blower would be reduced.

In the foregoing explanation of the operation of the air-handling unitof FIG. 1, it was assumed that the control unit 140 had been set toeffect movement of the vanes 52 and 56 to their minimum-flow positionbefore it caused the motor of blower 130 to start operating, and that ithad been set to cause that blower to operate at full speed before itcaused the valve controller 136 to open valve 134. If desired, thecontrol unit 140 could be set to cause the motor of blower 130 to startoperating even before the control unit caused the vanes 52 and 56 tomove to their miminum-flow position. Also, that control unit could beset to cause valve 134 to open before that blower reached its maximumspeed. However, the air-handling unit of FIG. 1 would provide maximumutilization of the warm air from the plenum between member 38 andceiling 39, would minimize the amount of heat that had to be supplied toheat source 126, and would minimize the amount of power that had to besupplied to the motor of blower 130, if that motor was not started untilthe vanes 52 and 56 reached their minimum-flow position and if the valve134 was not opened until that blower had begun operating at full speed.

The control unit 140 can be adjusted, at the factory or at a buildingsite, to initiate and conclude the full-open to minimum-flow movementsof the vanes 52 and 56 at selected temperature levels, to initiate andconclude the operation of the motor of blower 130 at selectedtemperature levels, and to initiate and conclude the opening of valve134 at selected temperature levels. As indicated hereinbefore, thoseselected temperature levels can be made to be discrete or to overlap. Asa result, the air-handling unit of FIG. 1 can provide almost any desiredsequence of control operations.

It will be noted that the air-handling unit of FIG. 1 can respond todifferences between the set point of thermostat 138 and the temperatureof the air adjacent that thermostat to selectively provide cold air,cool air, warm air or hot air. Further, it will be noted that the changefrom cold air to cool air is a progressive change rather than an on-offchange. Similarly, the changes from cool air to warm air and from warmair to hot air are progressive changes rather than on-off changes.Further, it will be noted that the change from cold air to cool air iseffected automatically. Similarly, the changes from cool air to warm airand from warm air to hot air are effected automatically.

If the control unit 140 were to be set to cause the blower 130 to startoperating before vanes 52 and 56 were moved to their minimum-flowposition, air would be continuously supplied to room 37, regardless ofwhether that air was cold, cool, warm or hot. Such an arrangement wouldbe desirable, because it would make certain that the room 37 wasventilated continuously.

The preceding portion of the description has explained how theair-handling unit of FIG. 1 can progressively supply cold, cool, warmand hot air to room 37. Where the temperature of the air adjacentthermostat 138 initially is below, rather than above, the control rangeof that thermostat, the output of that thermostat will cause controlunit 140 to produce outputs which will cause motor 70 to hold vanes 52and 56 in their minimum-flow position, will cause blower 130 to operate,and will cause valve controller 136 to open valve 134. As thetemperature of the air adjacent thermostat 138 moves up to the lowerlimit of that control range, the valve 134 will be permitted to close,but the blower will continue to operate at full speed. If thetemperature of the air adjacent thermostat 138 rises above that lowerlimit but has not yet reached the set point of that thermostat, thecontrol unit 140 will reduce the speed of blower 130. If the temperatureof that air rises to that set point, the blower will be permitted tocome to rest. Any further increase in the temperature of that air wouldcause the vanes 52 and 56 to move out of their minimum-flow position,and thereby permit cold air to pass between them and to aspirate coolair from the lower part of room 37. If the temperature of the airadjacent thermostat 138 tended to continue to rise, the vanes 52 and 56would be moved to their full-open position to provide maximum coolingeffect.

The inclined portion of the upper wall 82 of housing 80 is bent topermit that housing to extend under the blower 130 and under theenclosure 128. If ample horizontal space was available in the plenumbetween horizontal member 38 and ceiling 39, that upper wall could bemade planar, and that wall would be displaced laterally from that blowerand that enclosure.

If, due to the air pressure developed by the blower 130 or due todownstream pressure, the pressures at the right-hand faces of thebackdraft dampers 96 and 93 fail to remain below the pressures at theleft-hand faces of those backdraft dampers, those backdraft dampers willmove to their closed positions in abutting relation with the screens 92and 94, respectively. At such time, those backdraft dampers will preventescape of air past them into the wall 20. As a result, those backdraftdampers readily permit the aspiration of cool air into the housing 80but will substantially prevent all loss of air past them from thathousing.

The portion of the control unit 140 which controls the actuation ofmotor 70 can be set to respond to different values of the output fromthermostat 138. As a result, the temperature level at which the vanes 52and 56 are first moved inwardly and away from the resilient stops 102and 104 can be adjusted. Similarly, the temperature level at which thosevanes will move into their minimum-flow position can be adjusted. Theportion of the control unit 140 which controls the actuation of themotor for the blower 130 can be set to respond to different values ofthe output from thermostat 138. As a result, the temperature level atwhich that motor begins to operate can be adjusted. Similarly, thetemperature level at which that motor reaches its full operating speedcan be adjusted. The portion of the control unit 140 which controls theactuation of valve controller 136 can be set to respond to differentvalues of the output from thermostat 138. As a result, the temperaturelevel at which the valve 134 is opened can be adjusted. Further, itshould be noted that the settings of the three portions of the controlunit 140 can be adjusted independently of each other.

The use of a thermostat which can provide a variable output can becombined with the use of a control unit which can provide a variableoutput to enable the air-handling unit of FIG. 1 to provide any desiredrange of operation of vanes 52 and 56, of blower 130, and of heat source126. However, the cost of such a control unit, and the cost of avariable speed motor for that blower and of a variable-flow valve 134can make the overall cost of a system using that air-handling unit toohigh for some buildings. The use of a less expensive control unit, of aless expensive motor, and of an on-off valve can materially reduce thecost of a system which uses the air-handling unit of FIG. 1. Even wheresuch a control unit and motor and valve are used, the air-handling unitof FIG. 1 will provide comfort for the occupants of room 37 whileeffecting substantial savings in the heat supplied to heat source 126and in the power supplied to the motor for blower 130.

One arrangement which would be economical to use and which would enablethe air-handling unit of FIG. 1 to provide comfort while effectingsubstantial savings in energy would utilize a plural-speed, rather thana variable speed, motor. Another arrangement which would be economicalto use and which would enable that air-handling unit to provide comfortwhile effecting substantial savings in energy would utilize vanes 52 and56 that were settable in a full-open position, in one intermediateposition, and in a minimum-flow position. A very inexpensive arrangementwould utilize vanes 52 and 56 that were settable in full-open, in oneintermediate, and in minimum-flow positions, would utilize an on-offblower motor, and an on-off valve. Importantly, regardless of the natureof the motor and valve and controls used for the air-handling unit ofFIG. 1, that unit can provide comfort while effecting substantialsavings in energy, as long as it can aspirate cool air into the cold airfrom the conventional low pressure cold air duct, can reduce the flow ofcold air to a minimum, can draw warm air into the inlet of blower 130when warm rather than hot air is required, and can add heat to initiallywarm air. As a result, it should be apparent that the air-handling unitof FIG. 1 is very versatile and can be used with control equipment ofdiffering degrees of sophistication.

It should be noted that ducts, plenums, or other air-confining passagescould be used to guide air from the opening 36 to the opening 34 inFIG. 1. Those ducts, plenums, or other air-confining passages could bemade from sheet metal, fiberglass, furrings and wallboard, or otherconventional construction materials. The use of the spaces between thestud 16 and adjacent studs avoids the cost of ducts, plenums or otherair-confining passages.

Referring to FIG. 2, the numeral 144 generally denotes a wall of abuilding; and a header 146 is located at the top of that wall. A stud148, plus other studs not shown, extends downwardly from that header toa sill, not shown. The numeral 150 denotes wallboard, plaster-on-lath,or the like which defines the left-hand face of wall 144; and thenumeral 152 denotes wallboard, plaster-on-lath, or the like whichdefines the right-hand face of that wall. The numeral 154 denotes anopening in the left-hand face of wall 144; and the numeral 156 denotesan opening in the right-hand face of that wall which is in registerwith, but which is considerably larger than, opening 154.

The numeral 158 denotes a conventional low pressure, cold air duct whichextends through the openings 154 and 156. Tape, not shown, will be usedto seal the joint between the outer surface of that duct and the opening154. The left-hand end of a tubular socket 160 telescopes over, and issecured to, the right-hand end of duct 158. A hinge 162, that iscomparable to hinge 50 of FIG. 1, secures a vane 166 to the upper wallof socket 160. A hinge 164, which is comparable to hinge 54 of FIG. 1,secures a vane 168 to the lower wall of that socket. The numeral 170generally denotes a linkage which is similar to the linkage constitutedby axle 58, lever 60, links 62 and 64, crank arm 66, and connecting rod68 of FIG. 1. A motor 172, which is similar to motor 70 of FIG. 1, canact through the linkage 170 to cause the vanes 166 and 168 to assume aminimum-flow position, a full-open position wherein the free endsthereof abut resilient stops 196 and 198, or any desired intermediatepositions. In that minimum-flow position, the free ends of vanes 166 and168 will be spaced apart sufficiently to permit the cold air, from duct158, which passes between them to aspirate air through the spacesbetween those free ends and resilient stops 196 and 198.

The numeral 173 denotes an angle iron at the upper edge of opening 156,and the number 175 denotes an angle iron at the lower edge of thatopening. The numeral 174 generally denotes a housing which encloses thetubular socket 160 and the vanes 166 and 168. That housing has a topwall 176 which has a left-hand horizontal portion, a portion thatinclines downwardly from top left to lower right, and adownwardly-directed, vertical, right-hand portion. That housing also hasa bottom wall 178 which has a left-hand horizontal portion, a portionwhich inclines upwardly from lower left to upper right, and anupwardly-directed, vertical, right-hand portion. The side walls ofhousing 174 are generally hexagonal in configuration. The left-hand endof a duct 194 telescopes into the right-hand end of the housing 174; andangle irons 193 and 195 are secured, respectively, to the top and bottomof that duct. The top wall 176 will be releasably secured to angle irons173 and 193, and will abut the upper edges of the side walls. The bottomwall 178 will be releasably secured to angle irons 175 and 195, and willabut the lower edges of those side walls. Tape 180 seals the jointbetween the left-hand edge of housing 174 and the right-hand face ofwall 144.

The numerals 182 and 184 denotes screens which are comparable to thescreens 92 and 94 of FIG. 1. The numerals 186 and 188 denote backdraftdampers which are comparable to the backdraft dampers 96 and 98 ofFIG. 1. Those backdraft dampers normally are in planar condition and inengagement with the right-hand faces of screens 182 and 184; but theywill respond to even slight reduced pressures at the right-hand facesthereof to assume the open positions shown by FIG. 2.

The numeral 190 denotes a heat source which is interposed between screen182 and the vane 166; and the numeral 192 denotes a heat source which isinterposed between screen 184 and the vane 168. The resilient stops 196and 198 are mounted within the left-hand end of duct 194. The numeral197 denotes a control unit which can respond to a thermostat, not shown,like the thermostat 138 of FIG. 1 to cause motor 172 to provide thedesired positions for the vanes 166 and 168 and to cause the heatsources 190 and 192 to provide desired values of heat when warm air isdesired.

The wall 144 has an opening, not shown, in the right-hand face thereofwhich is close to the bottom of the room above which the air-handlingunit of FIG. 2 is located. A grille, not shown which is similar to thegrille 44 of FIG. 1, is disposed in that opening. That grille willpermit air to enter, and to pass upwardly in, that wall.

The air-handling unit of FIG. 2 primarily differs from the air-handlingunit of FIG. 1 in not having a blower. As a result, the air-handlingunit of FIG. 2 will be able to supply cold air, cool air and warm air,but will not be able to supply untempered hot air.

If the temperature of the air adjacent the thermostat, not shown whichcontrols the control unit 197, is above the upper limit of the controlrange of that thermostat, the outputs from the control unit 170 willkeep the heat sources 190 and 192 from providing heat, and will causethe motor 172 to hold the vanes 166 and 168 in their full-open position.At such time, the cold air from duct 158 will pass directly into theduct 194 without aspirating any air into it. Consequently, maximumcooling effect will be provided at that time.

If the temperature of the air adjacent that thermostat is below theupper limit of the control range, but is above the set point, of thatthermostat, the control unit 197 will keep the heat sources 190 and 192from supplying heat, but will cause the motor 172 to dispose the vanes166 and 168 in positions intermediate their full-open and theirmaximum-flow positions. At such time, cold air from the duct 158 willpass between those vanes to enter duct 194, and that cold air willaspirate air inwardly from the housing 176. That aspirated air will bedrawn upwardly through the wall 144 from the grille, not shown, in theright-hand face of that wall; and, because that air was close to thefloor of the room in which the thermostat is located, that air will becool. The addition of that cool air to the cold air passing between thevanes 166 and 168 will tend to cause the temperature of the air adjacentthe thermostat to move downwardly to, and then remain at, the set pointof that thermostat. The movement of the vanes 166 and 168 away fromtheir full-open position will reduce the horsepower hours needed tooperate the primary air-moving unit; and the cooling effect of the coolaspirated air will reduce the horsepower hours needed to operate theprimary refrigeration unit. As a result, the air-handling unit of FIG. 2makes it possible to save energy.

If the temperature of the air adjacent the thermostat is at or below theset point of that thermostat, the control unit 197 will develop outputswhich will cause the motor 172 to dispose the vanes 166 and 168 inpositions intermediate their full-open and their minimum-flow positions,and will cause the heat sources 190 and 192 to provide heat. As cold airflows from duct 158 between the vanes 166 and 168, it will aspirate airfrom the housing 174; and that aspirated air will be warmed as it passesthrough the heat sources 190 and 192. The amount of heat supplied bythose heat sources will be a function of the difference between thetemperature of the air adjacent the thermostat and the set point of thatthermostat; and the greater that difference, the greater the amount ofheat that will be supplied by those heat sources. Even the minimumamount of heat which is supplied by those heat sources will reduce thecooling effect that is provided by the cold air from duct 158; and hencecool air, rather than cold air, will be supplied by the air-handlingunit of FIG. 2 whenever the temperature of the air adjacent thethermostat is at, or just below, the set point of that thermostat. Inthose instances when the temperature of the air adjacent the thermostatis appreciably lower than the set point of the thermostat, the controlunit 197 will cause sufficient heat to be supplied by the heat sources190 and 192 to cause the air which enters the duct 194 to be warm ratherthan cold or cool. As a result, the air-handling unit of FIG. 2 canprovide cold air, cool air or warm air.

The linkage 170 for the vanes 166 and 168 can be set to hold the freeends of those vanes spaced apart even when the output of the thermostatcauses the control unit 197 to provide an output calling for a minimumsupply of cold air. Alternatively, stops could be mounted at theinterior of the housing 174 to mechanically keep the free ends of thosevanes from moving into engagement with each other. In either event, theair-handling unit of FIG. 2 will always be able to supply a minimum flowof air to the duct 194; and hence that air-handling unit will be able tosupply ventilation to the rooms which are connected to the duct 194,irrespective of the temperatures of the air within those rooms.

Where the air-handling unit of FIG. 2 is connected to a duct that cansupply only cold air, that unit will be unable to supply un-tempered hotair to the duct 194; and, in such event, the latter duct should be usedto supply air only to those locations where hot air is not required, orwhere other heat sources supply heat to those locations. In such event,the unit of FIG. 2 will constitute a source of warm air which canaugment the heat supplied by those other heat sources, while alsoproviding ventilation air when those heat sources are active. However,if the air-handling unit of FIG. 2 were to be connected to a duct thatcould selectively supply cold, cool or warm air, that unit could supplycold, cool, warm or hot air to duct 194. As a result, that duct could beused to supply air to almost any desired location. In all events, theair-handling unit of FIG. 2 will continuously supply ventilation for anylocation to which it is connected by duct 194.

If desired, the air-handling unit of FIG. 2 could be manufacturedwithout the heat sources 190 and 192. In such event, a simpler controlunit 197 could be used; because that control unit would merely need toprovide an output which would control the motor 172. Where theair-handling unit of FIG. 2 was manufactured without those heat sources,and where it was connected to a duct that supplied only cold air, itwould be able to provide cold air or cool air but not warm air. However,where that unit was connected to a duct that could selectively supplycold, cool or warm air, that unit could supply cold, cool, warm or hotair to duct 194. Where, as indicated hereinbefore, the air that is drawnupwardly through the wall 144 enters that wall at a point close to thebottom of the room in which the thermostat is located, that air will addto the cooling effect provided by the cold air from duct 158. Ifdesired, however, the air which enters, and then moves upwardly through,the wall 144 to the housing 174 could be admitted close to the ceilingof the room in which the thermostat is located. In such event, that airwould tend to warm the air from duct 158. In the former event, theaspirated air would reduce the horsepower hours needed to operate theprimary refrigeration unit. In the latter event, the aspirated air wouldreduce the horsepower hours needed to operate the primary heat source.In both events, the positioning of the vanes 166 and 168 inwardly oftheir full-open position would reduce the horsepower hours required tooperate the primary air-moving unit. As a result, the air-handling unitof FIG. 2 makes it possible to save energy.

If desired, ducts, plenums, or other air-confining passages could beused to guide air from a room or other location to the screens 182 and184; and those ducts, plenums and other air-confining passages could bemade from sheet metal, fiberglass, furrings and wallboard, or otherconventional construction materials. Also, if desired, the air-handlingunit of FIG. 2 could be displaced from the wall 144, and the opening 156in that wall could be made just large enough to accommodate the duct158. In such event, any air which was aspirated into the housing 174would come from the plenum in which that air-handling unit is located;and that air would usually be warmer than the air adjacent thethermostat in the room which received air from the duct 194. As aresult, whenever the motor 172 moved the vanes 166 and 168 inwardly fromtheir full-open position, and where duct 158 supplied only cold air, theair which was aspirated into the housing 174 would tend to reduce thecooling effect of the air supplied to duct 194. If such a reduction incooling effect was all that was needed, the heat sources 190 and 192could be left out of the air-handling unit; but, if that reduction incooling effect was not sufficient, those heat sources could beincorporated into that air-handling unit and used to supply stillfurther heat to the air from duct 158.

As indicated in connection with the air-handling unit of FIG. 1, acontrol unit 197 could be used which could set the vanes 166 and 168 inany one of a number of positions intermediate their full-open andminimum-flow positions. Alternatively, a control unit could be usedwhich would set those vanes in their full-open, one intermediate, andminimum-flow positions. The use of the former control unit would providecloser control of the temperature of the air in the room with which thatcontrol unit was associated; but the latter control unit and the motor172 controlled thereby would be less expensive than would that formercontrol unit and the motor 172 controlled thereby.

Referring particularly to FIG. 3, the numeral 200 denotes a wall whichhas a window 206 incorporated therein. A framing member 202 underliesthat window, and that framing member helps support a window sill 204. Anair-discharge grille 207 is mounted within an opening in that windowsill. The numeral 208 generally denotes an under-the-window air-handlingunit which is provided by the present invention. The numeral 210 denotesthe inner wall of that unit; and that inner wall has avertically-directed major portion and an upwardly and inwardly inclinedminor portion at the top thereof. The numeral 212 denotes a U-shapedouter top wall for the unit 208, and the numeral 214 denotes a U-shapedouter bottom wall for that unit. End walls, not shown, interconnect theinner wall 210 with the U-shaped outer walls 212 and 214. The numeral216 denotes a hinge which secures a vane 220 to the inner portion of theU-shaped wall 214. A motor 222 and a linkage 224 are provided to disposethat vane in a minimum-flow position, in any one of a number ofpartially-open positions, or in a full-open position. If desired, thefree end of vane 220 could abut the inner wall 210, and thereby blockall flow of air from duct 232, when that vane is in its minimum-flowposition; or that free end could be displaced far enough from that wallto enable air from that duct to aspirate air in through the spacebetween that free end and a resilient stop 226 when that vane is in itsminimum-flow position. That stop is secured at the inner surface of theU-shaped wall 212, and that stop will be engaged by the free edge ofvane 220 when that vane is in its full-open position. The numeral 228denotes a heat source which is mounted intermediate the U-shaped walls212 and 214 of the unit 208; and an air-transmitting front cover 230 isprovided to conceal that heat source but to permit air to pass throughthat heat source. The numeral 232 denotes the air duct which extendsupwardly through the floor 234 of the building. The numeral 223 denotesa control unit which can be identical to the control unit 197 of FIG. 2;and that control unit will supply outputs to the motor 222 and to avalve controller, not shown, for the inlet valve of heat source 228. Athermostat, not shown, within the room, of which the wall 200, window206 and floor 234 are parts, will provide outputs that will actuate thecontrol unit 223.

If the duct 232 is connected to a source of low pressure cold air, coldair will tend to pass upwardly between inner wall 210 and vane 220 andthen discharge through grille 207. Whenever the temperature of the airadjacent the thermostat in the room is above the upper limit of thecontrol range of that thermostat, the control unit 223 will provide anoutput which will cause the motor 222 to hold the free edge of vane 220against the resilient stop 226. At that time, a maximum volume of coldair will flow from duct 232, through unit 208, and out through grille207.

In the event the temperature adjacent the thermostat is below the upperlimit of the control range, but is above the set point, of thatthermostat, the control unit 223 will provide an output which will causethe motor 222 to move the vane 220 away from the resilient stop 226, andhence into a partially-open position. The further that temperature isabove that set point, the smaller the opening between that stop and thefree edge of that vane. If that free edge is to be displaced from innerwall 210 when vane 220 is in its minimum-flow position, the motor 222and linkage 224 could be set to hold that vane away from that wall whenthat vane is in its minimum-flow position. Alternatively, stops could beprovided at the interior of the air-handling unit 208 to fix the maximumdistance through which vane 220 could be rotated in the clockwisedirection. In either event, air from duct 232 would be able to flowcontinuously upwardly through the air-handling unit and dischargethrough the grille 207; and this would be desirable because it wouldpermit continuous ventilating of the room. In the event the free end ofvane 220 engaged the wall 210 when that vane was in its minimum-flowposition, any heat in the heat source 228 would cause convection-typeair flow inwardly through front cover 230 and heat source 228 andupwardly through grille 207.

As the vane 220 is moved away from the resilient stop 226, the air whichmoves upwardly at the right-hand face of that vane will aspirate air,from the lower part of the room, into the air-handling unit; and thatair will mix with the air from duct 232 and be discharged through thegrille 207. The temperature of that aspirated air will be higher thanthat of the cold air from duct 232; and hence that aspirated air willtend to reduce the cooling effect of that cold air.

As the vane 220 is rotated away from the resilient stop 226, it willreduce the total amount of air which can move upwardly from duct 232. Asa result, fewer horsepower hours will be needed to operate the primaryair-moving unit. The reduction in cooling effect, which is provided bythe aspirated air, will reduce the number of horsepower hours that arerequired for the heat source which supplies heat to the room. On bothgrounds, the air-handling unit is able to save energy.

If the temperature of the air adjacent the thermostat is at or below theset point of that thermostat, the control unit 223 will cause the heatsource 228 to supply heat. That heat will warm the air which is drawninwardly through the front cover 230, through that heat source, and thenaspirated into the air which moves upwardly from duct 232. The amount ofheat which is supplied by the heat source 228 will be a function of thedifference between the temperature adjacent the thermostat and the setpoint of that thermostat; and, the closer that temperature is to thatset point, the less heat will be supplied by that heat source. Theamount of heat which can be supplied to the aspirated air by that heatsource is variable enough to make the air, which issues from grille 207,be cool or warm. In the latter case, a reduction in the number ofhorsepower hours required to operate a primary heat source for the roomcan be effected.

Where the air-handling unit of FIG. 3 is connected to a duct that cansupply only cold air, that unit will be able to supply hot air only ifthe vane 220 engages the wall 210 when that vane is in its minimum-flowposition; and that hot air will be limited in volume, because it will beconvection-type hot air. However, where that unit is connected to a ductwhich can selectively supply cold, cool or warm air, that unit cansupply cold, cool, warm, hot or convection-type hot air.

The air-handling unit of FIG. 3 is compact; and hence it can fit neatlywithin the space below the window sill of many a room. In any room wherea limited amount of heat is all that will ever be needed, and where onlya cold air duct is available, that air-handling unit can obviate thecost of providing a primary heat source for that room. Even in abuilding where only a cold air duct is available, and hence a primaryheat source is needed for a room, the augmentary heat, which theair-handling unit of FIG. 3 can provide, will permit savings in energyas well as constant ventilation of that room without the discomfortwhich could result if the cold air from duct 232 was not warmed.

As indicated in connection with the air-handling unit of FIG. 1, acontrol unit 223 could be used which could set the vane 220 in any oneof a number of positions intermediate its full-open and minimum-flowpositions. Alternatively, a control unit could be used which would setthat vane in its full-open, one intermediate, and minimum-flowpositions. The use of the former control unit would provide closercontrol of the temperature of the air in the room with which thatcontrol unit was associated; but the latter control unit and the motor222 controlled thereby would be less expensive than would that formercontrol unit and the motor 222 controlled thereby.

In the foregoing descriptions of the air-handling units of FIGS. 2 and3, it was pointed out that the ducts 158 and 232 could be selectivelyconnected to sources of cold air, cool air or warm air. If desired,those ducts could, in warm or hot weather, be connected to a source ofcold air and could, in cool or cold weather, be connected to a source ofwarm air. One such source of warm air could be a space, within thebuilding in which those air-handling units are located, where the airtemperature was well above the set points of the thermostats in therooms to be supplied with air by duct 194 or by grille 207. Where thoseair-handling units received warm air from ducts 158 and 232, heat fromthe heat sources 190 and 192 or from the heat source 228 could add tothe heat from that warm air to adequately heat the rooms that were to besupplied by duct 194 or by grille 207.

It should also be noted that where the ducts 158 and 232 were connectedto sources to warm air, the air-handling units of FIGS. 2 and 3 couldcirculate warm air through un-occupied rooms, thereby keeping thetemperatures therein well above freezing without any need of supplyingheat to the heat sources 190 and 192 or to the heat source 228. Such anarrangement would reduce the heat energy that had to be supplied tothose heat sources, and yet would prevent cold-induced damage to thoserooms.

Referring particularly to FIG. 4, the numeral 238 generally denotes awall of a building; and a header 240 is provided at the top of thatwall. A stud 242, plus other studs not shown, extends between thatheader and a sill, not shown. The numeral 244 denotes wallboard,plaster-on-lath, or the like which defines that right-hand surface ofwall 238. An opening 246 is provided in wall 238 to accommodate a duct248; and tape, not shown, will seal the joint between that opening andthe outer surface of that duct. The duct will be connected to aconventional source, not shown, of low pressure, cold air.

The numeral 250 generally denotes an air-handling unit which has a topwall 252, a bottom wall 254, an end wall 256, a side wall 258, and acorresponding side wall, not shown. The side wall 258 and that otherside wall have their edges screwed, or otherwise secured, to the edgesof top wall 252 and end wall 256. The numeral 260 denotes an angle ironwhich extends between side wall 258 and the other side wall of theair-handling unit 250 to subdivide the left-hand side of that unit intotwo openings. The numeral 262 denotes an angle iron frame which boundsthe left-hand edge of the housing of the air-handling unit 250. Thenumeral 264 denotes an opening in the bottom of that air-handling unit;and a discharge outlet 290 has the upper end thereof disposed withinthat opening and has the lower portion thereof forming part of a ceiling292. An angle iron 259 is adjacent the left-hand edge of opening 264;and the bottom wall 254 is releasably secured to that angle iron and tothe bottom of angle iron frame 262, and it will abut the bottom edges ofside wall 258 and of the other side wall. The numerals 266 and 268denote openings in the side wall 258; and those openings can beconnected to distributor-type ducts. An opening, not shown, is providedin the end wall 256; and that opening can be connected to adistributor-duct which is indicated by dotted lines in FIG. 4. Thenumeral 270 denotes a heat source which is mounted within the unit 250;and a baffle plate 272 underlies that heat source. That baffle platewill coact with the top wall 252, the side wall 258, and with the otherside wall not shown, to confine air for movement through that heatsource. The numeral 274 denotes a multi-vane blower which has the outletthereof secured adjacent the heat source 270.

The numeral 276 denotes a screen which extends from the left-hand endedge of baffle plate 272 to an angle iron 279 adjacent the bottom wall254 of unit 250; and that screen inclines downwardly from upper left tolower right at an angle of about four degrees to the vertical. Backdraftdampers 278, which can be identical to the backdraft dampers 96 and 98of FIG. 1, are mounted at the right-hand face of screen 276. When thepressures at the opposite faces of those backdraft dampers are the same,those backdraft dampers will be planar and will abut the right-hand faceof screen 276. Also, when the pressures at the right-hand faces of thosebackdraft dampers exceed the pressures at the left-hand faces of thosebackdraft dampers, those backdraft dampers will be planar and will abutthe right-hand face of screen 276. However, those backdraft dampers willrespond to even very slight reduced pressures at the right-hand facesthereof to bow to the open positions shown by FIG. 4.

The numeral 280 denotes a screen which is similar to the screen 276; andthat screen extends from the top wall 252 to the angle iron 260. Thatscreen inclines downwardly from upper left to lower right at an angle ofabout for degrees to the vertical. The numeral 282 denotes backdraftdampers which can be identical to the backdraft dampers 278; and, whenthe pressures at the opposite faces of those backdraft dampers are thesame, those backdraft dampers will be planar and will abut theright-hand face of screen 280. Also, when the pressures at theright-hand faces of those backdraft dampers exceed the pressures at theleft-hand faces of those backdraft dampers, those backdraft dampers willbe planar and will abut the right-hand face of screen 280. However,those backdraft dampers will respond to even very slight reducedpressures at the right-hand faces thereof to bow to the open positionsshown by FIG. 4.

The numeral 284 denotes butterfly vanes or dampers that are pivotallymounted adjacent the discharge end of duct 248. A motor 286 and alinkage 288 of standard and usual design can set and hold those vanes ordampers in minimum-flow position, in open position, or in any desiredintermediate position. A control unit 293, which can be the same as thecontrol unit 140 of FIG. 1, is mounted on the air-handling unit 250.That control unit is connected to a thermostat, not shown, like thethermostat 138 of FIG. 1; and it also is connected to motor 286, to amotor, not shown, for the blower 274, and to a valve controller, notshown, for a valve in the inlet line for heat source 270. The numeral294 denotes a duct which is connected to the unit 250 and which has itsoutlet confronting the screen 280. The numeral 295 denotes a lightingfixture which is seated in the ceiling 292.

The air-handling unit 250, with its heat source 270, its blower 274, itsscreens 276 and 280, its backdraft dampers 278 and 282, its butterflydampers 284, its motor 286, and its linkage 288 can be shipped andinstalled as an integrated air-handling unit. After that air-handlingunit has been delivered to, and installed at, a building site, the ducts248 and 294, any distributor-ducts, and the discharge outlet 290 can besecured to it. The duct 248 can be connected to a conventional source oflow pressure cold air; and the duct 294 can be connected to an airdischarge grille, not shown, in the ceiling 292 of the room or to a warmspace in the building.

If the temperature of the air adjacent the thermostat in the room isabove the upper limit of the control range of that thermostat, thecontrol unit 293 will keep the motor of the blower 274 de-energized,will keep the heat source 270 from providing any heat, and will causethe motor 286 to hold the butterfly vanes 284 in their full-openposition. At such time, the low pressure cold air from duct 248 willflow past those butterfly vanes and then past the back-draft dampers 278for movement through the distributor-type ducts connected to theopenings 266 and 268, through similar openings in the air-handling unit250, and also through outlet 290 into the room of which the ceiling 292is a part. Some low pressure cold air may flow through the inactiveblower 274 and the heat source 270; but no air will escape through theduct 294, because the backdraft dampers 282 will be abutting the screen280. The resulting maximum cooling effect for that room will reduce thetemperature of the air within that room, and hence will cause thetemperature of the air adjacent the thermostat to decrease.

When the temperature of that air decreases to the point where it isbelow the upper limit of the control range, but is above the set point,of that thermostat, that thermostat will develop an output which willcause control device 293 to develop outputs that will continue to keepthe motor of blower 274 inactive and will continue to keep heat frombeing developed by heat source 270, but will cause motor 286 to move thebutterfly dampers 284 away from their full-open position to anintermediate position. As those vanes move to that intermediateposition, they will reduce the amount of cold air that will pass throughduct 248, and hence into the room. The cooling effect provided by thatcold air will cause the temperature of the air adjacent that thermostatto continue to decrease. As that temperature decreases, but while thattemperature is above the set point of that thermostat, the output ofthat thermostat will cause the control unit to continue to keep themotor of blower 274 inactive and will continue to keep the heat source270 from supplying heat. However, that output will change sufficientlyto cause the motor 286 to progressively move the butterfly vanes 284away from their full-open position as the temperature of the airadjacent the thermostat moves downwardly toward the set point of thatthermostat. The closer that temperature approaches that set point, thecloser the vanes 284 will be moved toward their minimum-flow position;and, conversely, the further that temperature is displaced from thatsetpoint, the further those vanes will be displaced from thatminimum-flow position.

If the temperature of the air adjacent the thermostat decreases to theset point of that thermostat, the output of that thermostat will causethe control unit 293 to provide outputs which will cause motor 286 tohold the vanes 284 in minimum-flow position, will cause the motor ofblower 274 to start operating at a low speed, and will continue to keepthe heat source 270 from supplying heat. The air which is drawn into theintake of the blower 274 usually will be warmer than the air adjacentthe thermostat; and hence a finite, albeit small, amount of heat will besupplied to air which flows downwardly through outlet 290. That heatwill tend to keep the temperature of the air adjacent the thermostatfrom falling below the set point of that thermostat.

However, if that temperature were to fall below that set point, thatthermostat would provide an output which would enable control unit 293to cause the blower 274 to operate at a higher speed. If the temperatureof the air adjacent the thermostat were to approach the lower limit ofthe control range of that thermostat, the control unit 293 would causethe blower 274 to operate at full speed. At such time, the warmth of theair entering the inlet of blower 274 would tend to keep the temperatureof the air adjacent the thermostat from decreasing any further. However,if that temperature were to fall below the lower limit of the controlrange of the thermostat, the control unit 293 would cause heat to besupplied to the heat source 270. That heat, plus the heat in the warmair supplied to the inlet of blower 274 by duct 294, would keep thetemperature of the air adjacent the thermostat from falling any furtherand, instead, would cause that temperature to rise toward the set pointof that thermostat. As long as the temperature of the air adjacent thethermostat is below the lower limit of the control range of thatthermostat, the control unit 293 will act to keep the blower 274operating at full speed and to keep the heat source 270 supplying heat.When the temperature of that air rises above that lower limit, thecontrol unit 293 will cause heat source 270 to become inactive; and, asthat temperature rises toward the set point of the thermostat, thatcontrol unit will reduce the speed of blower 274. The closer thattemperature approaches that set point, the slower the speed of thatblower; and, conversely, the further that temperature is below that setpoint, the faster the speed of that blower.

The backdraft dampers 278 will readily open whenever the vanes 284 arein partially-open or full-open positions. However, those dampers willclose whenever the blower 274 is operating; and they also will closewhenever the downstream pressure exceeds the pressure at the left-handfaces thereof.

Whenever the butterfly dampers 284 are moved out of their full-openposition, they will reduce the amount of cold air flowing through theduct 248; and hence they will reduce the horsepower hours of the primaryair-moving unit. When the blower 274 draws warm air inwardly from theduct 294, that warm air will reduce the durations of the heating periodsof the heat source 270, and also will reduce the amount of heat whichthat heat source must provide during those heating periods. As a result,the air-handling unit of FIG. 4 acts to reduce the amount of energyneeded to cool a building and also acts to reduce the amount of energyneeded to heat that building.

The duct 294 will be important in any community where a building codeprohibits the drawing of air into the inlet of blower 274 directly fromthe plenum above the ceiling 292. Also, that duct would be important ina cold climate where the air-handling unit was immediately adjacent aninsufficiently-insulated roof, and hence where the air in the plenumcould be colder than the air in the room of which the ceiling 292 is apart; because that duct could extend to, and communicate with, a spacein the building where warm air collects. In those communities where thebuilding codes do not require such a duct, and where the air in theplenum in warm, that duct can be eliminated. At such time, the air whichis drawn into the air-handling unit 250, when the blower 274 operates,will be drawn directly from the plenum above the ceiling 292; and thatair will be warmed by heat from the lighting fixture 295 and fromsimilar lighting fixtures. If desired, the duct 294 could be connectedto a passage within the wall 238 which was comparable to the passage inthe wall 20 in FIG. 1 or in the wall 144 of FIG. 2. Depending upon wherethe air was permitted to enter that wall, cool air or warm air wouldpass from duct 294 into the air-handling unit 250.

As indicated in connection with the air-handling unit of FIG. 1, acontrol unit 293 could be used which could set the butterfly vanes 284in any one of a number of positions intermediate their full-open andminimum-flow positions. Alternatively, a control unit 293 could be usedwhich would set those butterfly vanes in their full-open, oneintermediate, and minimum-flow positions. The use of the former controlunit would provide closer control of the temperature of the air in theroom with which that control unit was associated; but the latter controlunit and the motor 286 controlled thereby would be less expensive thanwould that former control unit and the motor 286 controlled thereby.

Referring particularly to FIG. 5, the numeral 298 generally denotesanother preferred embodiment of air-handling unit which is provided bythe present invention. That unit includes a housing 300 which has anupwardly-extending arm 301. Butterfly vanes or dampers 302 are mountedwithin the housing 300 adjacent the left-hand end thereof; and a motor304 and a linkage 310 control the settings of those vanes or dampers. Atubular connection 312 is connected to an opening in the arm 301; andthe housing 316 of a heat source 314 is connected to that arm by thattubular connection. Backdraft dampers 318, which can be similar to thebackdraft dampers 129 in FIG. 1, are mounted at the outlet of heatsource 314. A multi-vane blower 320 has the output thereof connected tothe input of heat source 314. A control unit 322, which can be identicalto the control unit 140 of FIG. 1, will supply outputs for the motor304, for the motor of blower 320, and for the control for heat source314.

Angle iron frames 324 and 326 are provided at the left-hand andright-hand ends, respectively, of the housing 300. The bottom wall 328of that housing is releasably secured to the angle iron frames 324 and326 and will abut the lower edges of the side walls of that housing.

It will be noted that the air-handling unit 298 resembles theair-handling unit 250 of FIG. 4, in that it has a left-hand inlet inwhich butterfly vanes are mounted, has a heat source, has a blower, andhas a control unit which can control the setting of those butterflyvanes, the speed of that blower, and the amount of heat supplied by thatheat source. The air-handling unit 298 primarily differs from theair-handling unit 250 in that the inlet of blower 320 opens directlyinto the space where that air-handling unit is mounted, whereas theinlet of blower 274 opens into air-handling unit 250 and is connected toa source of air by screen 280 and by duct 294--when such a duct is used.The air-handling unit 298 also differs from the air-handling unit 250 inbeing less expensive to manufacture.

The temperature-responsive sequence of operations of the air-handlingunit 298 can be identical to the temperature-responsive sequence ofoperations of the air-handling unit 250. As a result, thetemperature-responsive sequence of operations of the air-handling unit298 will not be described.

The backdraft dampers 96 and 98 of FIG. 1, the backdraft dampers 186 and188 of FIG. 2, and the backdraft dampers 278 and 282 of FIG. 4 can bemade in different ways and from different materials. However, a flexibleglass cloth is very useful, because it is fire resistant. In areas wherefire resistance is not of primary significance, rubberized fabrics orflexible plastics could be used in making the backdraft dampers. Astiffening rod or an elongated weight member is shown attached to thelower edge of each backdraft dmaper. That rod or member will not onlystiffen the lower edge of the backdraft damper, but also will serve tourge that backdraft damper toward its closed position.

It should be noted that the blowers 130, 274 and 320 of FIGS. 1, 4 and5, respectively, are displaced wholly away from the path for the lowpressure cold air in the air-handling units of those views. Similarly,it should be noted that the heat sources 126, 270 and 314 of FIGS. 1, 4and 5, respectively, are displaced wholly away from that path. This isvery desirable; because it completely obviates the frictional losseswhich would develop if that low pressure cold air had to pass throughthose blowers and through those heat sources. Similarly, it should benoted that the heat sources 190 and 192 of FIG. 2 and the heat source228 of FIG. 3, respectively, are displaced wholly away from the lowpressure cold air in the air-handling units of those views. This isdesirable; because it completely obviates the frictional losses whichwould develop if that low pressure cold air had to pass through thoseheat sources.

It should be noted that the air-handling units of FIGS. 1-3 aspirate aironly when the vanes of those units are displaced from their full-openpositions. This is desirable; because it enables those air-handlingunits to provide maximum cooling effect whenever those vanes are intheir full-open positions. In contrast, some prior air-handling unitshave continuously aspirated air into the cold air passing through them;and hence those units could never provide un-mixed cold air. It shouldalso be noted that as the air-handling units of FIGS. 1-3 aspirate coolair, they reduce the amount of cold air which is supplied by the primaryair-moving unit and they also reduce the amount of cooling effect whichmust be supplied by the primary refrigeration unit. This is desirable;because it reduces the horsepower hours required to operate the primaryair-moving unit and also reduces the horsepower hours required tooperate the primary refrigeration unit.

The air which is drawn into the air-handling units of FIGS. 1, 2, 4 and5 can, where suitable ducts are provided, be drawn from the lowerportions of rooms, from the upper portions of rooms, from warm spaces inbuildings, from cool spaces in buildings, or from the exteriors ofbuildings. As a result, such air can have desirable temperature andfreshening characteristics. By providing a number of air-handling units,of the type shown in any of FIGS. 1, 2, 4 or 5, throughout theair-distributing system of a building, it is possible to add air ofdesirably different temperatures to different areas of that building.This is in contrast to many prior air-distributing systems forbuildings, wherein substantially all of the air had to be supplied to,and pass through, the primary air-moving unit. By making it possible tosupply air at different places throughout an overall air-distributingsystem, the air-handling units of the present invention also make itpossible to reduce the overall size of the primary air-moving unit. Allof this means that the present invention makes it possible to supply airof desirably-different temperatures to various points in anair-distributing system and also makes it possible to reduce the totalamount of energy needed to operate that air-distributing system.

A number of air-distributing systems, such as double duct systems orsystems that use multizone air vents, which utilize hot and cold airducts also utilize cold and warm mixing dampers. Other air-distributingsystems cool all of the air which is supplied to various air-handlingunits in a building and then use heat sources in those units to warm orreheat the air. The present invention makes it possible to eliminatesuch cold and warm mixing dampers and also makes it possible to avoidthe energy losses involved in supplying cold air to the heat sources inthe air-handling units of a building, and yet makes it possible toprovide variable air volume in a large air-distributing system. Thepresent invention does so by mounting an air-handling unit in each zoneduct which extends from the primary air-handling unit. The air-handlingunit of FIG. 2 is particularly useful for this purpose; and, when it isused for that purpose, it could have the heat sources 190 and 192thereof removed.

The air-handling units of FIGS. 1-5 are easily incorporated intoair-distributing systems that are newly installed in buildings. Also,the air-handling units of FIGS. 1, 2, 4 and 5--and particularly the unitof FIG. 2--can be incorporated into already-installed air-distributingsystems in buildings. All that need be done is to cut out a section ofthe already-installed duct and replace it with one of those air-handlingunits.

The incorporation of any of the air-handling units of FIGS. 1, 2, 4 and5 into an already-existing air-distributing system would not permit theescape of cold air or of hot air, even if that air-distributingoccasionally developed larger-than-normal downstream pressures; becausethe backdraft dampers within that unit would prevent the escape of coldair and of hot air from that unit. The incorporation of any of thoseair-handling units into an already-existing air-distributing systemcould permit a desirable decrease in the average air pressure in theducts of that system; because the pressure drop across each of thoseunits can be as low as one hundredth of an inch water gauge. Any changesin the total amounts of air which must be supplied to the variousair-handling units can be effected by changing the positions of theadjustable, but normally-fixed, dampers within the various supply ductsof the overall air-distributing system. All of this means that thepresent invention permits aspiration of air into an air-distributingsystem--with resulting decreases in the horsepower hours required tooperate the primary air-moving unit and the primary refrigeration unit;and yet prevents loss of cold air or of hot air if larger-than-normaldownstream pressures develop.

The air-handling units of FIGS. 4 and 5 are shown with butterfly vanesinstead of elongated vanes of the type shown in FIGS. 1-3. In anyinstallations where the additional space required by such elongatedvanes is available and where the air aspiration provided by suchelongated vanes is desired, the air-handling units 250 and 298 couldhave the butterfly vanes thereof replaced by elongated vanes of the typeshown in FIGS. 1-3.

If desired, one of the air-handling units of FIGS. 1, 2, 4 and 5 couldbe mounted immediately adjacent the outlet of the primary air-movingunit of an air-distributing system. That air-handling unit would permitthe volume of air which was delivered to the air-distributing system tobe varied without varying the speed of that primary air-moving unit andwithout providing a bypass circuit around that air-moving unit. Further,that air-handling unit would make it possible to aspirate substantialquantities of make up air into the air which was delivered by thatprimary air-moving unit.

The air-handling units of FIGS. 1 and 2 could, if desired, be mountedin, or adjacent to, the discharge openings into rooms or other spaces.In such instances, the backdraft dampers and the heat sources of thoseunits could be deleted. Those air-handling units would be able to varythe volume of cold air supplied to the rooms served by them, and alsowould be able to induce make-up air into that cold air. In doing so,those air-handling units would facilitate the maintaining of the desiredtemperatures within those rooms, and also would provide desirably highvolumes of ventilating air for those rooms.

The air-handling units of FIGS. 1, 4 and 5 can be used to effectsubstantial savings in energy whenever the temperatures of the buildingin which they are installed need not be maintained at normal levels--ason week-ends or on holidays. Specifically, when the temperatures withinthe building need not be maintained at normal levels, the primary airsource for that building can be shut down, and the blowers of thoseair-handling units can be operated at low speeds and the heat sources ofthose air-handling units can be made to supply low values of heat. Theresulting finite, albeit small, movement of heated air will keep thetemperatures within the building from falling to undesirably-low levels,but will keep the total amount of heat energy and air-moving energyrequired by the building well below the amount which would be needed tomaintain the temperatures within that building at normal levels.

The air-handing units of FIGS. 1, 4 and 5 make it possible to providedesired values of air flow when cooling effect is being supplied to aroom, and yet make it possible to provide distinctively differentdesired values of air flow when heating effect must be supplied to thatroom. For example, a class room in a school might require from onethousand to fifteen hundred cubic feet per minute of air when coolingeffect is being supplied but could use as few as six hundred cubic feetper minute of air when heating effect is being supplied. Because thecontrol units of those air-handling units can be set to keep the heatsources of those air-handling units inactive as long as thoseair-handling units are supplying cold air, and because those controlunits can be set so the flow of cold air is minimized when the heatsources are activated, the present invention makes it possible to causethe volumes of air which are supplied during a heating cycle to bedistinctively different from the volumes of air which are suppliedduring a cooling cycle. As a result, the air-handling units of FIGS. 1,4 and 5 make is possible to save energy, and yet provide desirabletemperature control, by moving smaller air volumes during heating cyclesthan it supplies during cooling cycles.

As indicated hereinbefore, the blowers of the air-handling units ofFIGS. 1, 4 and 5 can be left inactive until the flow of cold air intothose air-handling units is minimized, or those blowers can be caused tostart operating while the vanes in those air-handling units are inintermediate positions close to their minimum-flow positions. Further,the heat sources of those air-handling units can be caused to supplyheat as soon as the blowers begin to operate, or they can be caused toremain inactive while those blowers supply warm make-up air duringperiods when the temperature adjacent the thermostat in the room isclose to the set point of that thermostat. This highly desirable abilityto provide discrete or overlapped supplying of cold air, cool air, warmair and hot air eliminates the need for precise calibration of thethermostat. Consequently, the movable temperature-setting element of thethermostat need only have the word WARM adjacent an arrow which pointsin one direction and the word COOL adjacent a second arrow which pointsin the opposite direction. The person who is to set the desiredtemperature for the room need only set that movable element in aninitial intermediate position, and then subsequently shift that elementin the desired direction to establish the desired temperature setting.

The control units 140, 197, 223, 293 and 322, for the air-handling unitsof FIGS. 1-5, are shown as being made of two or threecommercially-available control elements. If desired, however, each ofthose control units could be made specially as a single element ratherthan as a combination of a plurality of commercially-available controlelements.

The opening, in the air-handling unit 250 of FIG. 4, which permitsingress of make up air is shown in the left-hand end of the housing ofthat air-handling unit. However, if desired, that opening and the screen280 therefor, could be located in the portion of side wall 258 that isclose to the inlet of blower 274. Alternatively, that opening and thatscreen could be located in the portion of the opposite side wall that isclose to the inlet of that blower. Those openings could be made as"knockout" openings in those side walls, so either or both of thosesidewalls could be left intact. As a result, the air-handling unit ofFIG. 4 can be shipped to a building site; and can have the make-up airopening therein located at the most optimum place in the housingthereof.

The bottom wall 254 of that air-handling unit has been shown as made soit can be removed as a unit to provide ready and full access to theinterior of that air-handling unit. Also, that bottom wall can be madeto be imperforate and to extend all the way to the end wall 256. In thatevent, the opening 264 will be located in a duct which is connected to alarge outlet opening, not shown, in that end wall. Moreover, if desired,the openings 266 and 268 can be eliminated or made as "knockout"openings.

The blower 274 and the motor therefor preferably are mounted so they caneasily be lowered from their positions within that air-handling unit. Inthat event, they can easily be cleaned, repaired or replaced. Ifdesired, the two butterfly dampers 284 could be replaced by a singlelarge butterfly damper.

Whereas the drawing and accompanying description have shown anddescribed several preferred embodiments of the present invention, itshould be apparent to those skilled in the art that various changes maybe made in the form of the invention without affecting the scopethereof.

What I claim is:
 1. An air-handling unit which has a first inlet that isconnectable to a source of low pressure air, a second inlet throughwhich air can be aspirated into said air-handling unit, an outlet fromwhich air can issue, positionally adjustable volume-controlling meansintermediate said first and second inlets and said outlet which candirectly adjust the volumes of air that can pass from said first andsecond inlets to said outlet, said adjustable volume-controlling meansbeing adapted to respond to the movement of low pressure airtherethrough from said first inlet to said outlet to aspirate airthereacross into said air-handling unit through said second inlet solelyin response to a reduction in pressure adjacent said second inlet andacross said adjustable volume-controlling means due to the position ofsaid adjustable volume-controlling means and movement of airtherethrough and intermediate said first and second inlets and saidoutlet to permit said aspirated air to mix with said air from said firstinlet, and a backdraft damper adjacent said second inlet, said backdraftdamper being adapted to respond to a predetermined flowing air pressurelevel within said air-handling unit to permit aspiration of air throughsaid second inlet, said backdraft damper responding to a higherpredetermined flowing air pressure level within said air-handling unitto substantially block said second inlet, whereby said air-handling unitcan be used in an air-distributing system wherein the air pressure canbe below said predetermined air pressure level and can subsequently riseabove said predetermined air pressure level.
 2. An air-handling unit asclaimed in claim 1 wherein said source of low pressure air supplies coldair, and wherein said second inlet can communicate with a source of coolair, whereby said air which passes to said outlet is a mixture of coldair and cool air.
 3. An air-handling unit as claimed in claim 1 whereinsaid outlet can communicate with a room, wherein said source of lowpressure air supplies cold air, wherein said second inlet cancommunicate with a space within a wall of said room, and wherein air canbe drawn into said space within said wall from a point adjacent thefloor of said room, whereby said aspirated air is drawn into said spacewithin said wall from said point adjacent said floor of said room, andis moved upwardly through said space within said wall before it enterssaid second inlet.
 4. An air-handling unit as claimed in claim 1 whereinsaid source of low pressure air supplied cold air, and wherein saidsecond inlet can communicate with a source of warm air, whereby said airwhich passes to said outlet is a mixture of cold air and warm air.
 5. Anair-handling unit as claimed in claim 1 wherein said adjustablevolume-controlling means includes an elongated vane which is disposed soit is generally parallel to an air-flow path between said first inletand said outlet, and wherein a motor can move one end of said elongatedvane transversely of said air-flow path to vary the volume of air movingfrom said first inlet through said air-flow path.
 6. An air-handlingunit as claimed in claim 1 wherein said adjustable volume-controllingmeans includes an elongated vane which is disposed so it is generallyparallel to an air-flow path between said first inlet and said outlet,wherein a motor can move one of said elongated vane transversely of saidair-flow path to vary the volume of air moving from said first inletthrough said air-flow path, and wherein said one end of said elongatedvane varies the volume of said aspirated air as said one end is movedtransversely of said air-flow path to vary the volume of air moving fromsaid first inlet through said air-flow path, whereby said elongated vanecan respond to said motor to move transversely of said air-flow path andsimultaneously vary the volume of said aspirated air and the volume ofair moving from said first inlet through said air-flow path.
 7. Anair-handling unit as claimed in claim 1 wherein said adjustablevolume-controlling means includes an elongated vane which is disposed soit is generally parallel to an air-flow path between said first inletand said outlet, wherein a motor can move one end of said elongated vanetransversely of said air-flow path to vary the volume of air moving fromsaid first inlet through said air-flow path, wherein said one end ofsaid elongated vane varies the volume of said aspirated air as said oneend is moved transversely of said air-flow path to vary the volume ofair moving from said first inlet through said air-flow path, whereinsaid one end of said elongated vane increases the volume of saidaspirated air as it decreases the volume of air moving from said firstinlet through said air-flow path.
 8. An air-handling unit as claimed inclaim 1 wherein said adjustable volume-controlling means includes anelongated vane which is disposed so it is generally parallel to anair-flow path between said first inlet and said outlet, wherein saidadjustable volume-controlling means includes a second elongated vanewhich is disposed so it is generally parallel to said air-flow pathbetween said first inlet and said outlet, wherein a motor can providemovement of said elongated vanes to full-open position, to closedposition, and to a plurality of intermediate positions, wherein minimumair is aspirated through said second inlet whenever said elongated vanesare in said full-open position, wherein maximum air is aspirated throughsaid second inlet whenever said elongated vanes are in said closedposition, and wherein varying volumes of air are aspirated through saidsecond inlet when said elongated vanes are set in various of saidintermediate positions.
 9. An air-handling unit as claimed in claim 1wherein said adjustable volume-controlling means includes an elongatedvane which is disposed so it is generally parallel to an air-flow pathbetween said first inlet and said outlet, wherein the leading edge ofsaid elongated vane is held for pivotal movement, wherein a motor canmove the trailing edge of said elongated vane transversely of saidair-flow path to vary the volume of air moving from said first inletthrough said air-flow path, and wherein said backdraft damper is closerto said leading edge than to said trailing edge of said elongated vane.10. An air-handling unit as claimed in claim 1 wherein a heat source isprovided to supply heat to said aspirated air before said aspirated aircan mix with said air that moves from said first said inlet through saidair-flow path.
 11. An air-handling unit as claimed in claim 1 wherein aheat source is provided to supply heat to said aspirated air before saidaspirated air can mix with said air that moves from said first saidinlet through said air-flow path, and wherein said heat source islocated between said backdraft damper and the point where said aspiratedair can mix with said air that moves from said first said inlet throughsaid air-flow path.
 12. An air-handling unit which has a first inletthat is connectable to a source of low pressure air, a second inletthrough which air from a second source of air can be aspirated into saidair-handling unit, an outlet for said air-handling unit from which aircan issue, positionally adjustable volume-controlling means intermediatesaid first and second inlet and said outlet which can directly adjustthe volumes of air that can pass from said first and second inlets tosaid outlet, said air which passes from said first inlet to said outletaspirating air across said adjustable volume controlling means solely inresponse to a reduction in pressure adjacent said second inlet due tothe position of said adjustable volume-controlling means and movement ofair therethrough and intermediate said first and second inlets and saidoutlet into said air-handling unit from said second source of air, saidsecond source of air supplying air which has a temperature that isdifferent from the air supplied by said source of low pressure air, saidaspirated air mixing with said air that passes from said first inlet tosaid outlet, said adjustable volume-controlling means automatically, asit adjusts the volume of air that passes from said first inlet to saidoutlet, directly adjusting the volume of air which is aspiratedthereacross into said air-handling unit from said second source of air.13. An air-handling unit as claimed in claim 12 wherein an air-movingdevice can draw air from a third source of air and cause said air to mixwith said air that passes from said first inlet to said outlet.
 14. Anair-handling unit as claimed in claim 12 wherein an air-moving devicecan draw air from a third source of air and cause said air to mix withsaid air that passes from said first inlet to said outlet, and whereinsaid air-moving device is displaced from the path through which said airpasses from said first inlet to said outlet.
 15. An air-handling unit asclaimed in claim 12 wherein a heat source can supply heat to air whichis mixed with said air that passes from said first inlet to said outlet,and wherein said heat source is displaced from the path through whichsaid air passes from said first inlet to said outlet.
 16. Anair-handling unit as claimed in claim 12 wherein an air-moving devicecan draw air from a third source of air and cause said air to mix withsaid air that passes from said first inlet to said outlet, and wherein aheat source can supply heat to said air which is drawn from said thirdsource of air and is caused to mix with said air that passes from saidfirst inlet to said outlet.
 17. An air-handling unit as claimed in claim12 wherein an air-moving device can draw air from a third source of airand cause said air to mix with said air that passes from said firstinlet to said outlet, wherein a heat source can supply heat to said airwhich is drawn from said third source of air and is caused to mix withsaid air that passes from said first inlet to said outlet, and whereinsaid air-moving device and said heat source are displaced from the paththrough which said air passes from said first inlet to said outlet. 18.An air-handling unit as claimed in claim 12 wherein a backdraft damperis adjacent said second inlet, wherein said backdraft damper responds toa pressure differential in one direction to open and thereby permit airto be aspirated into said air-handling unit, and wherein said backdraftdamper responds to a pressure differential in the opposite direction toclose and thereby prevent undesired escape of air from said air-handlingunit.
 19. An air-handling unit as claimed in claim 12 wherein aperforate member is adjacent said second inlet, wherein a backdraftdamper is mounted adjacent to but inwardly of said perforate member,wherein said backdraft damper responds to a pressure differential in onedirection to open by moving away from said perforate member and therebypermit air to be aspirated into said air-handling unit, and wherein saidbackdraft damper responds to a pressure differential in the oppositedirection to move against said perforate member to close and therebyprevent undesired escape of air from said air-handling unit.
 20. Anair-handling unit as claimed in claim 12 wherein a perforate member isadjacent said second inlet, wherein a backdraft damper is mountedadjacent to but inwardly of said perforate member, wherein saidbackdraft damper responds to a pressure differential in one direction toopen by moving away from said perforate member and thereby permit air tobe aspirated into said air-handling unit, wherein said backdraft damperresponds to a pressure differential in the opposite direction to moveagainst said perforate member to close and thereby prevent undesiredescape of air from said air-handling unit, and wherein said perforatemember inclines inwardly from the top edge thereof to the bottom edgethereof to underlie and inwardly displace the lower edge of saidbackdraft damper, whereby said backdraft damper normally bears againstsaid perforate member to be in its closed position.
 21. An air-handlingunit as claimed in claim 12 wherein a backdraft damper is adjacent saidsecond inlet, wherein said backdraft damper responds to a pressuredifferential in one direction to open and thereby permit air to beaspirated into said air-handling unit, wherein said backdraft damperresponds to a pressure differential in the opposite direction to closeand thereby prevent undesired escape of air from said air-handling unit,and wherein said backdraft damper is flexible and can flex away fromsaid perforate member to open.
 22. An air-handling unit as claimed inclaim 12 wherein said adjustable volume-controlling means includes atleast one elongated vane that has one end thereof movable transverselyof the path through which said air passes from said first inlet to saidoutlet.
 23. An air-handling unit as claimed in claim 12 wherein saidadjustable volume-controlling means includes a plurality of elongatedvanes, wherein each of said elongated vanes has one end thereof movabletransversely of the path through which said air passes from said firstinlet to said outlet, and wherein said one ends of said elongated vanesare movable to a full-open position or to a minimum-flow position.